According to Mark Zuckerberg at last night's launch of Facebook's 'new home on Android': "We're not building a phone, we're not building an operating system. We're building something that's a whole lot deeper." Actually, that should be "a whole lot shallower."

Facebook's Home will provide an entire Facebook environment that loads and forms the dominant app by default on startup. As well as access to conventional Facebook and all its doings, the app will of course offer messaging (one of the things that worries telcos). At a later date it will almost certainly be upgraded to handle voice calls to other Facebook users (using RTS perhaps, or even a Skype-out equivalent to make standard calls) and there will probably be a version of Google's Hangouts video calling option (at a wild guess).

At launch it has a feature "Cover feed" that flags updates from friends and what might be a rather annoying "chat heads" that shows friends attempted communications and links into other mobile and messaging apps, roping them into the Facebook app.

Users can download Home free from the Google Play Store from this month and will currently work on the HTC One X, HTC One X+, Samsung Galaxy S III and Samsung Galaxy Note II. Facebook looks like it's planning to roll out to all platforms, of course. Just give it time.

"Home" will also be pre-installed on phones through the Facebook Home Program. HTC and AT&T are working together to push the onboard option in the US.

But really, the only interesting thing about Facebook's tardy 'skin' for Android is why it took so long to graft. And, perhaps, why other entities, including vendors with service/cloud aspirations of their own, haven't tried more skinning of their own.

The imminent arrival of a "Facebook Phone" has been popping up as a possibility for years now. Way back in 2010, for instance, rumours were circulating about a miraculous arrival (see - The Facebook phone.. or not. You decide ).

And at around the same time we interviewed Frank Meehan, CEO of INQ, about the likelihood of big media companies going to greater lengths to put themselves right at the top level of the smartphone, rather then being represented by a single icon somewhere on its many home screens. (see - It's Official - Welcome to an Android World!)

Indeed Android had originally been architected to enable this very thing - the idea being that phone vendors could differentiate by building their own user interface on top of the core code.

We all know the back-story with Facebook. Poor mobile performance but huge stock market expectations... panic button pushed in advance of IPO. The only reason Zuckerberg didn't get to market with some sort of Facebook skin a tad earlier was - by his own admission - that the company's developers couldn't wrestle HTML5 to the ground to create a cross-platform skin.

That would, in theory, have enabled him to address a broader market with fewer versions of the local client (HTML5 may not 100 per cent compatible across platforms). Now with the native app approach he must develop many separate apps, not just to address iPhone, Windows, Blackberry (and more) but to cater for different implementations of Android itself.

The phone won't just provide a route to Facebook, it will put users straight into Facebook... into the cloud and away from the phone's other on-board apps and the OS. And while users will still be able to bring up other apps, Zuck will be hoping he can keep them there for as long as possible using Facebook Apps and Facebook games and reading Facebook ads.

Whether a good proportion of Facebook's users take up Zuck's offer and fly into the parlour is beside my point... no doubt some will love it while many more, myself included, wouldn't touch it with 10 foot pole.

My point is that the move illustrates how the mobile OS has long ceased to be the commercial pivot point - the cloud is now where users are sent to be leveraged, controlled and milked.

So instead of struggling with a below-par OS (in terms of industry support and user acceptance - looking at you Nokia and Blackberry) those with ambitions to do a bit of milking would be better off going with Android (which Blackberry has half done) and then going for some real differentiation in services or handset build (or both) and using a skin to do the differentiation/milking bit. Nobody has yet convinced me that Nokia, for instance, wouldn't have built as good a set of phones as Samsung has by adopting Android under the skin.

Zuckerberg's 'Home' may or may not succeed - I think there's plenty of evidence that many Facebook users are already weary of being manipulated for ad fodder, so the idea that you'd want an immersive experience on your own handset with Zuck selling you off to the highest bidder is a bit difficult to swallow. But the skin will be there as an option and some users will no doubt love it and use it.

Even as a partial success it will show that cross-platform 'skin to cloud' is the way to build and maintain visibility now. My bet is that we'll even see telcos adopt it to present their own OTT-style services - perhaps even following the exact route that Zuckerberg did: failing first and early with HTML5 (Firefox OS) and then reverting to building an uber-app on the standard smartphone platform.